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DaveC (davecuny@gmail.com) on 12/5/07 wrote:
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>That would make sense, but when has Sun's MPU group ever made complete sense? :-p
>However, you're not really "shrinking" N3 if you ADD cores.

It depends on the cores. If they drop the many-thread-per-core approach they can cut on the multiple contexts every core has to support (register files, etc...) and also share L1s like Rock is supposed to do.

>Thing is, they have a adequately-performing core that's engineered for 8 threads
>per core, so why abandon the many thread idea for dual thread? Why not just beef up the cores?

Higher single-threaded performance I guess. If Rock cores are able to yield higher single-threaded performance and the very high resource usage levels of Niagara it would be certainly a good idea to reuse them in the low end.

>My guess is that N3 is very similar to Rock but w/out the scout threads and SMP.

Rock cores w/o scout threading don't make much sense IMHO as they wouldn't have any way to absorb stalls, however I guess you might be right on the SMP though. They might also be 'cut down' versions. Rock is supposed to be 4-way superscalar, corresponding T3 cores might be 2-way (like the current ones which are sort-of-2-way-but-not-really-superscalar).

Gabriele

PS: All of the above is just pure, unfounded, wild speculation on my part so take it for what it's worth